The present invention relates to an apparatus for mechanically removing water which is contained in the tissues, mainly tracheae and tracheids, of crude veneers which are relatively watery.
A crude veneer generally has a water content ranging from 30-200 percent and needs some treatment for dehydration to serve as a ply, for example. One implementation available for dehydration of crude veneers is mechanical drying which squeezes out water by compression, as proposed in Japanese Unexamined Patent Publication (Kokai) No. 48-49905 and others. A prior art apparatus for mechanical drying uses pressing elements such as so-called dry rolls which are each provided with tooth-like projections on its peripheral surface and pressed against the whole surfaces of a veneer to squeeze out water.
The problem with the prior art apparatus discussed above is that since the distance between the peripheries of the dry rolls except for the teeth, or bottom lands, is not greater than about 30-60 percent of the thickness of a veneer, the rolls cause a veneer to undergo plastic deformation over the entire surfaces against which the rolls are abutted, thereby noticeably reducing the thickness of the veneer. In addition, the prior art apparatus is unsuitable for use with knotty veneers because it would break and remove knots due to the plastic deformation during the course of dehydration.